(A) Field of the Invention
The present invention relates to a wavelength converter and green light source and projection apparatus using the same, and more particularly, to a wavelength converter equipped with light-filtering pattern and green light source and projection apparatus using the same.
(B) Description of the Related Art
Quasi-phase matching (QPM) is a technique for phase matching nonlinear optical interactions in which the relative phase is corrected at regular intervals using a structural periodicity built into the nonlinear medium, and the most popular case of interest in modern QPM technology is called frequency doubling or second harmonic generation (SHG).
U.S. Pat. No. 6,129,864 discloses a process for producing an optical waveguide substrate including a ridge-shaped structural portion containing at least an optical waveguide, with such process including the steps of forming an optical waveguide-forming layer on a substrate body to prepare a substrate workpiece, and forming said ridge-shaped structural portion at said substrate workpiece by grinding.
U.S. Pat. No. 6,631,231 B2 discloses an optical waveguide element including a three-dimensional optical waveguide of a bulky non-linear optical crystal, a substrate, and a joining layer made of an amorphous material. The substrate is joined to the optical waveguide via the joining layer.
U.S. Pat. No. 7,171,094 B2 discloses an optical waveguide device including a waveguide layer that converts a wavelength of incident light and emits converted light. In the waveguide layer, a ridge waveguide and slab waveguides are provided, the slab waveguides being formed on both sides of the ridge waveguide with recess portions intervening therebetween. The waveguide layer satisfies a multi-mode condition for the incident light, and light propagating through the ridge waveguide is in a single mode.
U.S. Pat. No. 7,236,674 B2 discloses an optical waveguide device having a substrate composed of a nonlinear optical material and a periodically domain-inverted structure having the same composition as the nonlinear optical material, where the domain-inverted structure has a refractive index distribution relying on the domain-inverted structure.
US 2005/0253055 discloses an MEMS oscillator, such as an MEMS scanner, which has an improved and simplified drive scheme and structure. Drive impulses may be transmitted to an oscillating mass via torque through the support arms. For multi-axis oscillators drive signals for two or more axes may be superimposed by a driver circuit and transmitted to the MEMS oscillator. The oscillator responds in each axis according to its resonance frequency in that axis. The oscillator may be driven resonantly in some or all axes. Improved load distribution results in reduced deformation. A simplified structure offers multi-axis oscillation using a single moving body. Another structure directly drives a plurality of moving bodies. Another structure eliminates actuators from one or more moving bodies, those bodies being driven by their support arms.